Try our new info resource - "Aladdin's Cave" (Main menu)Just added a separate link to Ash's Dropbox thread (shortcut)
Update:So I have changed the boot clamps to very nice Jubilee clamps and tightened them carefully. They surely hold the rubber manifolds firmer, but I still have the same erratic behaviour, no noticeable change at all. As soon as the engine is warming up (1 or 2 minutes max) idle starts jumping a bit and then spikes to 3k...then down under 1k for no apparent reason. Throttle is responsive and there is no real hang if I blip it.At this point I feel pretty confident it is not an air leak, so I will be tinkering with the advance mechanism springs, as an old post by Hondaman suggested weak springs (a common occurrence) could cause a similar behaviour.At this point I would also be curious to swap my (original) coils with good working ones just to rule out they have anything to do with it, but I don't really want to buy new ones right now without the certainty I actually need them...BTW I have tested mine with a voltmeter and they seem fine, but I wonder if they may start "acting up" once warm?
Having eliminated air leaks then it may we’ll be an issue with the advance mechanism, have you thought of hooking up a strobe timing light I think that would show if the timing was jumping around
Nope.
One thing I would like to add.....I know how frustrating it can be chasing problems like this, I spent weeks chasing around with an issue that I thought was down to air leaks (but wasn’t in the end). My bike had never idled very well and was always quite and to start despite having rebuilt the carbs and changed the carb brassware.In the end I got so fed up I bought a set of refurbished carbs from Gerben. Ok they cost 300 but I got 95 back in part ex for my old ones.Result bike starts first kick, idles like a dream.Sometimes it just pays to have a professional service the carbs that uses good quality brassware was my take homeMine is a 500 by the way with 069A carbs not a 550.
Listening to that video, does that ultra short high chirping sound, every now and then, not indicate some electric shorting? Or is it just the keys vibrating on the handlebars? I suppose there's no harm in checking if there's any intermittent arcing going on between plugcaps (and/or HT leads) and the head. Best seen in the dark.
Did you ever manage to get the carbs synced using a set of four gauges?I have a set but I’m in Cobham, Surrey.